-
- Posts: 8
- Joined: Tue Jan 09, 2018 10:21 am
- Location: CH
We have a project of screening drugs of abuse with GC-MS (GC: Agilent 7890, MS: Agilent 5977, Column: HP-MS).
We use the Agilent M2721 protocol (see below) with few modifications:
1) Hydrolysis of 1 mL urine with HCL 12N, 15 min, add the phosphate buffer and use NAOH to bring it to pH 6 after the hydrolysis
2) load 1 mL of the hydrolyzed urine and 1 mL of non-hydrolyzed urine into the Bond elut certify column using a vaccum manifold.
3) Elute a third fraction (containing Morphine and Benzoylecgonin) with 20% 2-propanol + 2% NH4OH + 78% CH2CL2 and derivatize with BSTFA (1% TMCS).
Reconstitution after evaporation is made into 20 uL of EtOAc for the acidic and basic fraction and BSTFA( 1% TMCS) for the third.
This allows us to detect all the desired drugs in SCAN MODE but there is an issue with the liner (Agilent 5190-2293). In order to keep our sensitivity, we have to change it really often, almost every run (20-30 sample's injections).
Is it something normal? Or do we do something wrong?
Would it be another solution in order to not change this liner too often?
Thank you for your help.
----------------------------------------------------------------------------------------
EXTRACTION OF DRUGS OF ABUSE
USING BOND ELUT CERTIFY
ANALYTE NAME/MATRIX
M2721
General Drug Screen
from Urine or Plasma
ANALYTICAL
TECHNIQUE
GC or
GC/FID
PRODUCT/PART NUMBER USED
130 mg Certify
1210-2051 or 1211-3050
section 1 - PRINCIPLE AND MECHANISMS
Basic, acidic and neutral drugs can be retained and selectively eluted using the ion
exchange, polar, and non-polar interactions of the Certify mixed mode sorbant.
section 2 - EXTRACTION METHOD
SAMPLE PREPARATION:
To 2 mL of either urine or plasma add 6 mL of 0.1 M phosphate buffer (pH 6.0).
Mix/vortex.
COLUMN PREPARATION/EXTRACTION:
1. BOND ELUT CERTIFY PREPARATION
2 mL CH3OH; draw through under vacuum.
2 mL 0.1 M phosphate buffer (pH 6.0); draw through under vacuum.
NOTE: Use a low vacuum (2 inches Hg) to prevent drying of sorbent.
2. SPECIMEN APPLICATION
Load at 1 to 2 mL/minute.
3. COLUMN RINSE
1 mL DI H2O; draw through under vacuum.
0.5 mL 0.01 M acetic acid; draw through under vacuum.
Dry column (4 minutes at 15 inches Hg).
50 uL CH3OH (no vacuum).
Dry column (1 minute at 15 inches Hg).
4. ELUTE ACIDIC AND NEUTRAL DRUGS (FRACTION A)
4 mL acetone:chloroform (50/50); draw through slowly under low vacuum (1 inch
Hg).
5. ELUTE BASIC DRUGS (FRACTION B)
2 mL EtOAc/NH4OH (98/2); use no vacuum.
section 3 - ANALYSIS
Add 100 uL of a 200 ug/mL Prazepam solution (internal standard). Mix/vortex. Evaporate each fraction to 100 uL at 40°C under N2. Inject 1 to 2 uL of each fraction into the gas chromatograph (GC).
CERTIFY GENERAL DRUG SCREEN ANALYSIS*
The following compounds have been extracted from urine and plasma samples using Certify extraction columns:
FRACTION (A): ACIDIC AND NEUTRAL DRUGS
Butalbital Clonazepam Methaqualone
Heptabarbital Diazepam Meprobamate
Hexobarbital Lorazepam
Metharbital Nitrazepam
Pentobarbital Oxazepam
Probarbital
Secobarbital
FRACTION (B): BASIC DRUGS
Amphetamine Levallorphan Procaine
Cocaine Mepivacaine Promethazine
Codeine Methamphetamine Trimipramine
Imipramine Morphine**
For more general information on these and other drugs of abuse, see John Wilson's "Abused
Drugs, A Laboratory Pocket Guide"; AACC Press; Washington, D.C.: 1990.
* Adapted from Chen, X.-H. et al. Journal of Forensic Sciences 1992, 37(1), 61-71.
** Requires 2 x 2 mL EtOAc/NH4OH (98/2) elution aliquots.